Odd intake compatibility question for Rover Tech types

[Hans]

I think I know the answer to this one, but I figured I'd ask those who might know for sure.

Since I am going to be doing this MegaSquirt computer for the EFI system, I can actually tune for radically different parts. SO, will the '99 "Thor-Motronic" style upper manifold fit onto the 3.9 lower manifold? I know that the sensors and such are different and I'll probably need to alter the throttle cable and a few other things, but as far as the engine itself is concerned, does this manifold physically fit? It almost appears that the lower manifold is the same for all of the engines.

-Hans

[Roadsiderob]

Hans,
The 'thor' upper manifold will not fit a 14cux/gems lower manifold...but you could just use the complete setup and fuel rail. The fuel system on the Bosch injection is set at 51psi and regulated by the in tank pump and is returnless (deadheads at the fuel rail). The 14CUX/GEMS use a vacuum controlled pressure regulator on the fuel rail with a return system to regulate the pressure to about 32/36psi. I would think working out the cooling system/thermostat/distributor/ignition system with this manifold setup would pose more of a challenge than the fuel system.
Rob

[Hans]

Yeah, the cooling issue would be a bit too much work to be worth it.

Since I'll be using an entirely different EFI system (MegaSquirt), the distributor and ignition issues don't matter. I could work out the fuel issues and all that if the Thor upper would mate to my existing lower.... but if I have to use the Thor lower and alter the cooling system, it becomes too much of a hassle. Maybe if I go with a 4.0 or 4.6 in the future, but that gets beyond the inexpensive and versatile concept that I am working on.

Since you seem to have a good bit knowledge, does the new Performance Distribtuors DUI systems fit into a NAS 3.9 block? (www.performancedistributors.com). A bit pricey for my blood, but I would think a 1987 distributor would be the same physically as a 1994. Given the issues that the Lucas ignition gives folks, going to the GM HEI would be a definite improvement.

[Roadsiderob]

Hans,
I'm not sure it would fit--depends on the clearance to the bracketry/alternator...there is also an issue of where to hook up the trigger wire for the fuel injection...the provided tach port may work. I had a customer that did a supercharged 4.6 in a DI and went with a Mallory unilite distributor and and aftermarket programmable Fuel injection...from Accel I think.
Cheers, Rob